The present invention relates to a method of controlling a vehicle and a system of controlling a vehicle, and particularly to a method of controlling a vehicle and a system of controlling a vehicle having an automatic transmission in the vehicle.
A vehicle of a manual transmission type is excellent in fuel economy compared to a vehicle mounting a transmission using a torque converter. However, coordination of the clutch and the accelerator at starting is difficult to be operated. If the coordination of the clutch and the accelerator at starting is not operated well, a large shock is generated at engaging the clutch, or rotation speed of the engine may be rapidly increased when the clutch pressure is insufficient, that is, what is called as a blowing-up phenomenon occurs. Further, when the clutch is suddenly engaged while rotation speed of the engine is insufficient, or when the vehicle is started to run on an uphill, the engine may be stopped, that is, what is called as engine stopping occurs.
In order to solve these problems, a system automatizing clutching and shifting using a mechanism of a manual transmission, that is, an automatized MT (an automatized manual transmission) has been developed. However, a driver sometimes feels incongruity because suspension of driving torque occurs by disengaging and engaging of the clutch in the control at shifting gear in the conventional automatized MT (the automatized manual transmission).
A system disclosed in, for example, the Japanese Patent No. 2703169 is known. In the system, an assist clutch of a friction transmission means is added to the conventional automatized MT (the automatized manual transmission) to perform rotation speed synchronization and torque transmission for shifting gear by controlling the assist clutch when shifting is performed.
Further, a system disclosed in, for example, the Japanese Patent No. 2898405 is known. In the system, in order to rapidly perform rotation speed synchronization in a vehicle of such a kind, a target value of an input rotation speed of the transmission is set depending on a driving condition of the vehicle, and a torque of the assist clutch is set so that the input rotation speed of the transmission is operated according to the target rotation speed.
In the vehicles of such a kind, a feeling of shifting strongly depends on a waveform of the output shaft torque of the transmission in what is called as an inertia phase in which using the assist clutch, the rotation speed of the input shaft of the transmission is synchronized with the rotation speed of a gear train next engaged with an engaging clutch. Therefore, in the case of setting a target input shaft rotation speed first, and then controlling the clutch torque so that the input shaft rotation speed may follow the target rotation speed, as disclosed in Patent No. 2703169 or Patent No.2898405, the torque of the assist clutch generated as the result is not always formed in a desired waveform as a shifting feeling.